RC Pier Live Load Generation

I am aware of the the two live load generation methods (constant spacing and variable spacing), and have a good understanding of their differences.  

Specifically for the variable spacing method, would it be possible to add an input for the user to define the lane width they want to use?  RC Pier uses 10 feet, and positions all adjacent trucks 10 feet apart.  There is currently no option to change this. While i acknowledge that using 10 ft is conservative, I would like to follow AASHTO and use a 12 ft lane.  The 10 ft lane load and truck load should then move transversely within the 12 ft lane to produce maximum effects.  

For example:  currently, a load case with 3 or 4 trucks would have them all spaced 10 ft apart.  According to AASHTO, 2 of these trucks could be 10 ft apart (if one were on the right side of the lane and the other on the left side of the lane), but the 3rd and 4th trucks should be 12 ft apart.

Using the constant spacing method is not a better option, because it simply starts at one gutterline and keeps adding trucks until no more fit.  It does not move the first truck to other potential controlling locations, such as with one wheel directly over an interior beam.

Thanks

Jeff